Process for sheening pile fabrics



easemee wuss KtitKtNUt Search Room 'FVUNITIED STATES PATENT OFFICE JamesDouglasMacMahon, Niagara Falls, N. Y., I .assignorto .Thei Mathieson Alkali Works, Inc., .New .York, N.IY., a corporation of Virginia No Drawing. Application October :21, 1942, "Serial No. 462,839

.12 Claims. (Cl.18 128) lThls': inventionrelates' to an improvedprocess for :shee ningfle fabrics, and more particularly to a'method for'sheeningthe pile'of wool rugs, carpets, and fabrics of a like nature, all of -which will bereterredto herein as wool rugs.

"The process commonlyknown as rug sheening has come to be or increasing importance in the manufacture of pile fabrics. The methods oftreatment'known to and used by the art-most or 'which have involved treatments with solutions containing bleaching powder or sodium 'hy'po chlorlte, have notjin spite of attemptsatrig-id control; produced completely-satisfactory results.

Operators employing the methods of the art or variations of them have'encountered numerous difliculties and found that they possess many serious disadvantages. Outstanding among these have-been the inability oi such methods-to give reproducible results. This is-a particular disadvantage in the manufacture of-carpets wherea certain pattern and'finish must remain substantially uniform throughout-a'large quantity of material which is manufactured over -a long period of time. For various reasons which are morefullydiscussed below, it has been'very dimcult if not impossible toobtain'a constant sheen anda uniform shade of color by "the useof the methods of sheening known" to the art. In many cases it hasbeenj found that a treatment appropriate toproduce the desired sheenalso causes aloss .or fading of the color in the pile and thus in the fabric itself, or sometimes introduces an entirely different tint in the starting color.

A further .outstandingdifiiculty has been that a serious loss of tensile strength of the ,pile often accompanies the sheening process. This, of course, greatly reduces th life of th .fahric by lowering its resistance to wear. Certainnof .the known methods have alsobeen found to possess atendency to remove the'twist fromthe'yarn, thus'makingssheening diflicultand causing the finished :Droduct -to have an undesirable .fuzzy appearance. .This tendsto ,disturbthe original demarkations inthe patterns. Further disadyantages which the proposed methods :of sheen- -ing= have. failed to overcome are the: running ftm vgethcrpf colors .in pattern fabrics, uneven or 'streakyi sheening, E and variations in :color or degree of :sheen" from the top of thexpileitO the bottom.

his the primary objectof the present invention to provides. chemical method Of pile fabric lheening which will eliminateor minimizethe obove recited dlmcultiesand disadvantageswhich attend the use "of the methods known tdtheiart The "process of sthe present invention accom vplishes this 'by providing *a: chemical treatment which produces a minimum loss of fiber strength and at the sam time produces a uniform maxi mum sheen without altering or-destroyingtthe color or th texture of the fabric. This. invention, furthermore, provides a process :which easily operated and .oontrolled.

I have found that" a high degree of sheen :may be attained and the disadvantages hitherto involved either eliminated or minimized by subjecting the pile of: the rug'to a two-stag rtreatmentin successive aqueous'solutions, theiinitial stage comprising treatment in asolution containing hydroxyl ions and 'peroxide in concentrations within the limits: prescribed below, and the second stage comprising treatment in a dilute but'well regulated solution of-a ypochlorite. The'presencegwithin the pres Edliifiitshi concentrationsyof the peroxiderand'of the hydroxyl ions in the first-stage treating solution 'andof the hypochlorite-in thesecond-stage treating solution are" the prerequisites for the effectiveness of the treating process.

' The peroxide may be supplied tothe solution by dissolving therein a peroxide forming material which may be organic or inorganic in character. Inorganic peroxide forming materials include the peroxides'suchas hydrogen peroxide, alkalimetal peroxides (sodium peroxide for exampleLalkaline earth metal peroxide (barium peroxide for example) and per salts which in aqueous solution formihydrogen peroxide, sodium perphosphate, sodiumperborate, sodium percarbonate, and the like, being examples of such per salts. Organic peracids and their salts also serve assources of hydrogen-peroxide, peracetic acid, perbenzoic acid, sodium peracetate and sodium perbenzoatebeing examples of. suchorganic materials. .Organic and organo-metallic salts of hydrogen peroxidasuch as. tetramethyl ammonium peroxide and triethyltinperoxide may also .be usedfor this purpose.

The hydroxyl ions essential for the effectiveness 'oftheperoxide solution may be supplied by any suitable hydroxyl forming com-pound capable. .of producing hydroxyl ions in such concentrations'as to provide a pH within the range prescribed hereinafter. Thus, inorganic .bases suchas the alkali and alkaline earthzhydroxides (sodiumxhy- "this purpose.

sufilciently soluble in water also may be used as a, source of the hydroxyl ions. Tetramethyl ammonium hydroxide and triethyltin hydroxide are illustrative examples of such compounds. In general, salts of strong bases and weak acids, whether organic or inorganic, hydrolyze in water to form free hydroxyl ions and these salts may also be used as a source of hydroxyl ions. Trisodium phosphate, sodium carbonate, sodium tetraborate sodium acetate, and the like, are appropriate examples of such salts. Hydroxyl ions may also be supplied by hydrolysis of the peroxide forming material where such material hydrolyzes in water to form hydroxyl ions. In an operation employing hydrogen peroxide, H202, as the source of peroxide, the hydroxyl ion concentration may be supplied for example by an alkali metal hydroxide, such as sodium hydroxide. In operations in which alkaline peroxides or per salts are employed, sodium peroxide, NazOz, for example, a sufficient hydroxyl ion concentration may result from the hydrolysis of the peroxide or per salt in aqueous solution. In some cases, an additional quantity of hydroxyl ion may be added with advantage.

In the second stage of the process the treatment is effected with hypochlorite chlorine such as is provided by alkali metal and alkaline earth metal hypochlorites. High test hypochlorite, bleaching powder, sodium hypochlorite and lithium hypochlorite may be used advantageously for Where a considerable portion of sheening is to be done by hypochlorite in this second stage, necessitating a relatively high concentration of available chlorine, I prefer to use, for example, a calcium hypochlorite substantially free of calcium chloride and containing a minimum of free lime. A rinsing step preferably follows both the initial treatment by the alkaline peroxide solution andalso the second stage hypochlorite treatment. The process may be completed by a souring treatment in accordance with known methods. The present process may be carried out in any apparatus suitable for subjecting fabrics to successive treatments in different solutions with intermediate rinses.

pile itself. I am unable to state definitely the reasons for the improved results obtained by the use of the herein described process, but it would appear that the reaction taking place is a very limited one which tends to change the imbricated surface of the fiber to a relatively smooth surface which has an increased tendency to reflect directly rather than scatter light rays. In this way the desired sheen is imparted to the fabric. It

,is to be understood, however, that my invention is not limited to any particular hypothesis as to the mechanism of the process.

As indicated above the difficulties encountered in producing or enhancing the sheen on wool rugs are more pronounced with certain weights of rug and colors than with others. An improved process for sheening the pile of wool rugs which It has been found that in most cases best results are obtained when the solution during the first stage is maintained at a temperature between about and 120 F., and at a somewhat higher temperature in the second stage, and when the period of treatment is from about 15 minutes to about one hour. The treatment of my pres,-

' ent invention may be followed by rinsing and souring steps in accordance with known methods.

Wool fiber is composed of a cortex covered with epithelial scales. While I am unable to state definitely the course of the chemical reaction occurring between a substance such as bleaching powder and a wool fiber in a single stage sheening process, it appears that the imbricated or serrated surface of the fiber is first attacked and the protecting scales removed. This exposes the fibrous material itself to the destructive actionof involves a two-stage treatment comprising treating the fabric for a limited period of time with a dilute caustic solution and thereafter with an aqueous solution of calcium hypochlorite is described and claimed in Patent No. 2,185,210, granted to myself, Lorenzo D. Taylor and Varton 'M. Kalusdian. The present process may beused alternatively with the said two-stage process with equal advantage on many types of rug and in certain instances with superior results. This is particularly true on types of rug which, due to an easily altered color, or to particular pile characteristics, are difiicult to sheen without adverse-:- ly affecting either the color or the pile or both.

For example, on certain rugs th first stage arkali treatment-of the referred'to process has a tendency to muss the pile which may, to a certain extent, be corrected by the subsequent hypochlorite treatment. When an alkaline peroxide solution is used in the first step, however,

the twist of the yarn is not materially disturbed,

even in those cases in which alkali alone has a detrimental efiect. Furthermore, it is possible, other conditions being the same, to obtain a desired sheen with a lower concentration of available chlorine in the second step when peroxide is present in the first step. Inasmuch as hypochlorite has greater tendering action than peroxide this has the advantage of minimizing tensile strength losses in the pile of the fabric. I have also observed that in certain instances, notably with some shades of green, the presence of peroxide in the caustic step aids in color retention by preventing the inception of a slight yellow tint in the green color which sometimes accompanies the use of alkali and hypochlorite without peroxide.

In many instances a satisfactory sheen may be attained with no loss of coloror fiber degradation by the use of a single-stage treatment involving a solution containing hydroxyl ions and peroxide.

Such a process is described and claimed in a coin the two-stage process, the less expensive hy pochlorite serving to accomplish some of the re sults caused by the peroxide The reaction of hypochlorite is more rapid and hence the total treating time for a rug is decreased. A higher sheen may be obtained in rugs whose color is not adversely affected by the hypochlorite. Certain shades of blue have been ..found to be'unduly grams per liter of 100 volume hydrogen perox ide solution. The designation 100 volume peroxide is used in the trade to indicate that one volume of the aqueous solution employed is capable of liberating 100 volumes of oxygen. Such a solution is approximately 27-28% hydrogen peroxide, H202, by weight. -In cases where per salts or-other sources of peroxide are used directly, the limits of hydroxyl and peroxygen group concentrations should also be within the limits just stated. In certain instances, it is desirable to maintain a hydroxyl ion concentration in excess of that provided by hydrolysis of an alkaline peroxide or per salt where the peroxide or per salt is used as the source of the peroxygen group. This may be accom-' plishedby adding the necessary quantity of an alkali metal hydroxide, but the total hydroxyl ion concentration, including that produced by hydrolysis, (i. e. the pH) should nevertheless be within the above stated limits in order to produce best results. r

- The temperature of the solution during treatment during both stages is advantageously maintained between about 50 and about 120 F., but as in the .case of the concentrations of thereactants the temperature value giving the maxi-. mum sheen with the minimum of harmful effects must be determined for each particular type ofrug. In general it may be said that best results are obtained by operating during the first stage at approximately room temperatures, i. e. within the range ofabout 60 to 95 F. The tempera! ture used in this step should also be chosen with regard to that used in the hypochlorite stage which is advantageously higher than that em-.- ployed in the first stage. The most desirable time of treatment in the first step must be determined with respect tothe rug being treated, the solutions used, and the conditions to beused in the second step. In general a treating time within the range 15.minutes to 60 minutes will be satisfactory; a treatment approximating 30 minutes being particularly desirable.

.--.Following the treatment with the alkaline I r terially from bleaching powder or chlorinated lime both in chemical constitution and in contentv solution of the second stage should be such as to.

produce an available chlorine concentration within the limits 0.5 to 3.0 grams per liter, the exact amount depending largely on the fabric undergoing treatment, and being insufiicient to cause a substantial loss of tensile strength of the fiber and insufficient toalter the color of the pile. In

certain instances I have found that a concentration within these limits which is suitable for one peroxide .solution the rug is advantageously given a water rinse of from 2 to 5. minutes at about .90." F. It isthen subjected to treatment in an aqueous solution, of a hypochlorite, in which the concentration of available chlorine is insufficient tocause a substantial loss of tensile strength of the fiberand insufficient to alter the color of the pile. .T he time of treatment and temperature will .vary, depending on the type, weight and color of the rug being sheened, the strength of the hypochlorite solution and the conditions and results obtained in the first stage.

To obtain the full benefits of the process of the present invention when using calcium hypochlorite in the second stage of the prooesathe cal- ,cium hypochlorite should be substantially free of calcium chloride and containing a minimum of free lime. The presence of free lime, in the second or hypochlorite stage of the process sometimes tends to increase the sheen obtained, but if present to excess frequently causes undesirable changes in the color of the fabric. Calcium hypochlorite compositions prepared as described in United States Letters Patent No. 1,787,048, granted to Robert B. MacMullin and Maurice C. Taylor on an application filed August 16, 1928, are particularly useful in the process of the present invention. Such calcium hypochlorites are not to be confused with conventional bleaching powder or chlorinated lime. Theydiifer marug may be toogreat for another rug similarto the first in all respects exceptcolor. The concentrations in such cases must be kept within an even narrower range.

The effectiveness of the alkaline peroxide solution used in the first stage of my process may be enhanced by the additional presence of a detergent or wetting agent such as those referred to in. the above-identified copending application of, myself and Lorenzo D. Taylor, and with the same beneficial results enumerated therein. Such de tergents or wetting agents are preferably synthetic water-soluble detergents or wetting agents such as the higher organic sulfates, sulfonates or quaternary ammonium compounds (sodium lauryl sulfate, sodium oleyl sulfate, sodium dodecyl benzene sulfonate, and trimethyl octyl ammonium chloride, for example). The detergent, or a mixture of such detergents, is pref erably used in concentrations ranging from about 0.1 to 1.0 gram per liter and, with particularv advantage, within the range of about 0.1 to 0.5 gram per liter.

Following the hypochlorite treatment the rug,

is with advantage subjectedto one or preferably two 5-minute water rinses at a moderate temperature, F. for example. This may be followed by a souring step comprising treatment in any appropriate dilute acid solution such as one containing 2 cc. per liter formic acid.

The following specific examples will serve to illustrate the process of the invention as well as to indicate, by comparison of Example II with Example I the improved results obtained in one specific instance when compared to an operation in which peroxide is not present in they first step.

- Example I A sample of a Wilton rug of green color and medium weight was treated in a washwheel containing 3 liters of an aqueous solution made up from 5 g. p. l. NaOH having a pH of about 13, and the treatment continued for 30 minutes at a'temperature of 65 F. The rug was rinsed in water at a temperature of 90 F., following which 3 liters of a calcium hypochlorite solution of the above recited properties was introduced. This solution had an available chlorine concentration of 0.75 g. p. l. and was maintained at a temperature of approximately 90 F. during a 15 minute treatment. The rug was then given two 5 minute water washes at 90 F. and soured in a dilute TREATMEM' rt CHEMECAL MODIFL fiiillQN F TEXTILES 6: H8533,

a neea Example II ,Asimilar sample, from thesame greenrug used in Example I was subjected to &similar treat! ment, the exception being that the solution in the first step of this example was made up from g. p. l. NaOH and also 1.45 g. p. l. 100-volume H202, this being equivalent to approximately 0.37 g. p. l. of the peroxygen group (and having a pH of about 12.5), and in the second stage the concentration of available chlorine from the hypochlorite approximated 1.5 g. p. 1. After drying, the rug was found to possess the desired high degree of sheen, the, pile to bein better condition with no noticeable fiber degradation, and in addi-: tion the original green color remained unchanged shOWing no trace, of the yellow tint obtained when peroxide was notpresent in the first step.

Example III v A similar sample of the same green rug was treated in a Solution made up from 5 g, p. l. of sodium hydroxide, 4 g. p. l. of 100-volume hydrogen peroxide for a period of '30 minutes at a temperature of 70 F. The ruggwas rinsed in water at a temperature of 90 Rand then treated with a sodium hypochlorite solution containing 0.75 g. p. l. of available chlorine. This treatment was of minutes duration at approximate- 13; 90 F. The rug was given two 5-minute water washes at 90- F. and soured in a dilute formic acid solution for ten minutes. The color, sheen and pile of the rug were substantially the same as obtained by the process of Example II.

E xample, I V

- A similar samplefrom the same green rug used in Example I'was treated in a wash wheel con; taining 3 liters of aqueous solution made up from 5 g. p. 1. of sodium hydroxide, 3 g. p. l, of 'l00-Volumehydrogen peroxide, during theperiod of minutes at a temperature of about70FL After this first treatment, the rug was rinsed inwater atabout 90 F; and treated with 3 liters of a hypochloritesolution containing 1 g. p. l. of available chlorine as lithium hypochlorite. This treatment lasted for 15 minutes at 90F. afterwhich the rugwas rinsed twice and soured with dilute formic acid solution as before. The color, sheen and pile of the rug after this treatment were substantially the same as found in Example II.

This. application-is a continuation-in-part of my application Serial No. 310,575, filed December 22, 1939.

I claim:

1. The method of sheening the pile of wool rugs which comprises subjecting the pile to treatment in an aqueous solution containing hydroxyl ions and a peroxygen compound, the concentration of the said compound in the solution being equivalent to not less than about 0.14 nor more than about 2 grams of the peroxygen group, -Oz, per liter and the pH of the solution being between about 7.5 and 13, and thereafter subjecting the pile to treatment in an aqueous solution of a hypochlorite in which the concentration of available chlorine is within the range of about 0.5 to 3 grams per liter and insufficient to cause a substantial loss of tensile strength of the fiber of the pile and insufiicient to alter the color of the pile.

GROSS REtERENCt Search Room 2. The method of'sheening the pile of wool rugs which comprises subjecting the pile to treatment in an aqueous solution containing hydroxyl ions and a peroxygen compound, the concentration of the said compound in the solution being equivalent to not less than about 0.14 nor more than about 1.5 grams of the peroxygen group, O=2i--, per. liter and the pH of the solution being between about 7.5 and 13, and thereafter subjecting the pile to. treatment in an aqueous solution of a hypochlorite. in which the concentration of available chlorine is within therange of about 0.5 to 3. grams per liter and insufiicient to cause a sub-1' stantial-loss of tensile strength of the. fiber of the pile and insufficient to. alter thecolor of the pile..

,3. .Themethod of sheening the pile of wool rugs which. comprises subjecting the pile to treatment in an aqueous solution-containing hydroxyl'ions and aperoxygen compound, the concentration of said compound. in thesolution being equivalent .to not less than about 0136 nor more. than. about 0.8 grams Qf'the peroxygen group, -O2,' per liter and the pH of the solution being. between about 10 and.12.5,, and thereafter subjecting the pileto treatment in an aqueous solution of a hypochlo..- rite in which the concentration of availablechloe rine is within. the range of about 0.5? to 3- grams per liter and insufficientto cause a substantial loss. oftensile strength of thefiber of. the pile and insufficient to alter the color of the pile.

4. The method of sheening the pile of woolrugs which ,comprisessubjecting the pile to treatment in an: aqueous solution containing hydroxyl ions and a peroxygen compound, the concentration of thesaid compound in the solution being equivalent to not less than about 0.14v nor more than about 2grams0f theperoxygen, group, O2-, per liter and the pH of the solution being between about 7.5 and 1,3, and thereafter subjecting the pile .to treatment in an aqueous, solution of calcium by? pochlorite in ,which-theconcentration of avail? able chlorine is within the range of about 0.5 to 3 grams per liter and insufficient to cause asubJ- stantial loss of; tensile strength of the fiber of the pile and insuflicient to alter the color of the pile.

5. The method of sheening the pile of wool rugs, which comprises subjecting the pile to treatment in an aqueous solution containing hydroxyl ions and a peroxygen compound, the concentra-. tion of the said compound in the solution being equivalent to not'less than about 0.14 nor more. than about 2 grams oftheperoxygen group, O2--, per liter and the pH of the solution being between about, 7.5and 13, and thereafter subiccting the pile to treatment in an aqueous solution of sodium hypochlorite in which the concentration of available chlorine is within the range of about 0.5 to 3 grams per liter and in'sufiicient to cause a substantial loss of tensile strength of the fiber of the pile and insufiicient to alter the color of the pile.

6. The method of sheening the pile of wool rugs which comprises subjecting the pile to treatment in an aqueous solution containing hydroxyl ions and a peroxygen compound, the concentration of said compound in the solution being equivalent to not less than about 0.14 nor more than about 2 grams of the peroxygen group, O2, per liter and the pH of the solution being between about 7.5 and 13, and thereafter subjecting the pile to treatmentin an aqueous solution of lithium hypochlorite in which the concentration of available chlorine is within the range of about 0.5 to 3 grams per liter and insufficient to cause a substantial loss of tensile strength of the fiber of the pile and insufiicient to alter the color of the pile.

7. The method of sheening the pile of wool rugs which comprises subjecting the pile to treatment in an aqueous solution of an alkali metal hydroxide and hydrogen peroxide, the concentration of the hydrogen peroxide in the solution being equivalent to not less than about 0.14

' nor more than about 2 grams of the peroxygen ment in an aqueous solution of sodium hydroxide and hydrogen peroxide, the concentration of the hydrogen peroxide in the solution being equivalent to not less than about 0.14 nor more than about 2 grams of the peroxygen group; ---O2-,'

per liter and the pH of the solution being between about 7.5 and 13, and thereafter subjecting the pile to treatment in an aqueous solution of I a hypochlorite in which the concentration of available chlorine is within the range of about 0.5 to 3 grams per liter and insufiicient to cause a substantial loss of tensile strength of the fiber of the pile and insufiicient'to alter the color of the pile.

-9. The method of sheening the pile of wool rugs which comprises subjecting the pile to treatment in an aqueous solution of sodium hydroxide and hydrogen peroxide, the concentration of the hydrogen peroxide in the solution being equivalent to not less than about 0.14 nor more than about 2 grams of the peroxygen group, -O2-, per liter and the pH of the solution being between about 7.5 and 13, and thereafter subjecting the pile to treatment in an aqueou solution having dissolved therein a hypochlorite containing upwards of 50% available chlorine, the concentration of available chlorine in said solution being within the range of about 0.5 to 3 grams per liter but less than an amount sufficient to introduce an appreciable loss of tensile strength in the fiber of the pile and less than anamount sufficient to alter the.color of the pile.

10. The method of sheening the pile of wool rugs which comprises subjecting the pile to treatment in an aqueous solution of sodium peroxide, the concentration of the peroxide in the solution being equivalent to not less than about 0.14 nor more than about 2 grams of the peroxygen' group, TO2-, per liter and the pH of the solution being between about '7 .5 and 13, and thereafter sub jecting the pile to treatment in an aqueous solution having dissolved therein a hypochlorite containing upwards of 50% available chlorine, the concentration of available chlorine in said solution being within the range of about 0.5 to 3 grams per liter but less than an amount sufflcient to introduce an appreciable loss of. tensile strength in the fiber of the pile and less than an amount sufficient to alter the color of the pile.

I :11. The method of sheening the pile of wool rug which comprises subjecting the pile to treatment in an aqueous solution of sodium perborate, the concentration of the perborate in the solution being equivalent to not less than about 0.14 nor more than about 2 grams of the peroxygen group, -O2, per liter and the pH of the solution being between about 7 .5 and 13, and thereafter subjecting the pile to treatment in an aque-- ous solution having dissolved therein .a hypochlorite containing upwards of 50% available chlorine, the concentration of available chlorine in said solution being within the range of about 0.5 to 3 grams per liter but less than anamount suflicient to introduce an appreciable loss of tensile strength in the fiber of the pile and less than an amount sufiicient to alter the color of the pile.

12. The method of sheening the pile of. wool rugs which comprises subjecting the pile to treatment in an aqueous solution containing hydroxyl ions, a peroxygencompound and a synthetic organie water-soluble detergent selected from the class consisting of higher organic sulfates, .sulfonates and quaternary ammonium compounds free of fatty acid ester substituents, the concentration of the said peroxygen compound in the solution being equivalent to not less than about 0.14 nor more than about 2 grams of the-peroxygen group, -02-, per liter, the pH of. the

solution being between about 7.5 and 13, and the detergent concentration being between about 0.1 and 1.0 gram per liter, and thereafter subjecting the pile to treatment in an aqueous solution of a hypochlorite in which the concentration of available chlorine is within the range of about 0.5 to 3 grams per liter and insufficient to cause a substantial loss of tensile strength of the fiber of the pile and insuificient to alter the color of the JAMES DOUGLAS MACMAHON. 

